A loose fence post usually has one of two causes. It was not tamped in properly when the post was first put in, and as the ground settles, a gap opens around the post allowing it to shift. The second cause is that the post has rotted or broken off below the ground. Replacing or tightening a post is not difficult -- you can do it independently and save the cost of hiring a fence contractor.
Fixing Loose Fence Posts
Test the post to determine the cause of its being loose. Push the post back and forth and study the ground. If the post is intact the whole length of it will move. If the post is broken in the ground the post will rock and twist at the point of the break.
If the post is not broken, check the soil around it. If the soil is loam or sand, try tamping the area immediately around the post. This will force the soft soil down around the post, tightening it. Fill additional dirt in as you tamp it down. If the post is now tight, then your work is done.
If the ground is too hard to tamp, or if the post is broken, then it will have to be pulled out of the ground. Depending on what kind of fence it is, the wire, boards or rails will have to be unfastened from the post.
Position a bumper jack or a handyman jack against the post, with the hook against the post. Wrap a chain or nylon strap tightly around the lower end of the post and over the hook on the jack. Begin ratcheting the handle on the jack, lifting the post up out of the hole. When the post clears the hole, finish by manually lifting it out and laying it on the ground. Disconnect the jack.
Dig the post hole out larger with the post hole digger, Set the dirt just to the side of the hole. You will use it to fill in around the post. If there is a broken piece of post in the hole, remove it. When you have dug out the hole, put the post back in. If the post was broken, put a replacement post in the hole.
Slide the post level over the top of the post and fix it to the upper end of the post. This type of level has a 90-degree base with vertical and horizontal levels on both sides of the base. Fit the level snuggly onto a corner and tighten it with the elastic band. The level can also be held on with a bungee cord. It must be tight.
Line the post up with the posts to either side of it. Once the post is lined up, shovel dirt into the hole one-fourth of the way full. Straighten the post until the levels all show a straight and level post. Hold the post with one hand and the tamper in the other, tamping the dirt hard in the hole all around the post. Shovel in another few inches of dirt and tamp again. The post will begin to tighten; as it does you will no longer need to hold it up. Push the post as needed to keep the levels even.
Continue filling the hole and tamping the dirt until the hole is filled and the dirt tamped down hard around the surface. Reattach the wire, rails or boards. The post is now solid.